20946.first-pass.diff​ is a rough first-pass at adding/linking totals for sites, users, themes and plugins and adding the WordPress version info.

I don't think we should be mimicking the code in the current Right Now section, which is pretty terrible. It's not easy to remove items from this list (you need to use CSS), you can only add items to the bottom, and when you do so you have to manually add all the crappy markup around each item to match the existing items. The list of items should be an array with a filter on it rather than an action sitting at the bottom. This applies to the non-network admin Right Now widget too, but that's probably better addressed in another ticket.

Small one: "Create a new site|user" should really say "Add a new site|user" for consistency with terminology on the Sites and Users screens.

Easy enough. I also adjusted the percentage widths for the tables.

The list of items should be an array with a filter on it rather than an action sitting at the bottom. This applies to the non-network admin Right Now widget too, but that's probably better addressed in another ticket.

I agree, if not only because the code is verbose and repeated enough that it almost makes more sense to dump it out of an array.